The 60s are great speakers and I would certainly recommend them to anybody but *to me* they don't have the same detail, depth and dynamics that the 80s have, seems like the 80s just filled the room so easily and at lower listening levels the 80s seem like they stay more consistent with the detail

A sub can move more air, because of the bigger driver. Also, it just doesn't "cut off" at 80hz, there is a gradual slope or blend or hand off, whatever you want to call it...Frequencies below 80hz are non-directional, meaning you can't tell where they are coming from, which is the subs purpose.

I know that Randy

It was a simplified discussion. If it really did "cut off" at the set frequency, I would't bother trying anything new because it would be an instanateous step change on both sides and I would not have to even consider changing the XO frequency (for the sake of the speakers stepping on each other) in the first place. I think the key is choosing a XO point where the main is really rolling off (and the XO point contributes to it) and the sub is still there strong.